[By Associated Press] SEATTLE, Wash. Oct. 27-- Mill ions In dust and nuggets will, in the next few years, be taken out of the Cassiar district of British Columbia, which is destined to become one of the greatest gold producing centres on the continent.” This is the opinion of Captain Syd ney Barrington, veteran Stikine river mariner, whose line of passen ger and freight boats out of Wran gell, Alaska, had been carrying the gold-seekers to and from the new El Dorado for the past year. “The $25,000 panned last summer s nothing but a sample of what the district contains,” he declared were Monday.